code: def add_buttonbar(self):
      self.button_bar = wx.Panel(self)
      self.button_bar_sizer = wx.BoxSizer(wx.HORIZONTAL)
      self.sizer.Add(self.button_bar, 0, wx.LEFT | wx.TOP | wx.GROW)
  
      for i, (mt, func) in enumerate(functions):
          bm = mathtext_to_wxbitmap(mt)
          button = wx.BitmapButton(self.button_bar, 1000 + i, bm)
          self.button_bar_sizer.Add(button, 1, wx.GROW)
          self.Bind(wx.EVT_BUTTON, self.OnChangePlot, button)
  
      self.button_bar.SetSizer(self.button_bar_sizer)
  
file_path: matplotlib/galleries/examples/user_interfaces/mathtext_wx_sgskip.py
imports: from io import BytesIO
  import wx
  import numpy
  from matplotlib.backends.backend_wx import NavigationToolbar2Wx
  from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg
  from matplotlib.figure import Figure
label_desc: Use image node_id 2 for calling the CanvasFrame obj's underlying member method code with example usage: obj.add_buttonbar() without return types